Water and soil samples from the vicinity of Agbabu bitumen field of Southwestern Nigeria, were analyzed qualitatively and quantitatively for 10 parent polycyclic aromatic hydrocarbons (PAHs) using gas chromatography coupled by flame ionization detector (GC-FID), in order to gather information on the degree of contamination by bitumen exploration and processing in this area. The total concentrations of 10 PAHs varied from 11.2 to 341.5 microg L(- 1) in water and from 101.5 to 209.7 ng g(- 1) dry weight in soils. The total PAH levels in water samples from all the sampling stations (except at station WB 11), were sufficiently high (> 10 microg/L) to cause acute toxicity to the exposed organisms. Special PAH compound ratios, such as phenanthrene/anthracene and fluoranthene/pyrene, were calculated to evaluate the relative importance of different origins. The collected data indicate pyrolytic and petrogenic sources. The anthropogenic PAHs, i.e., pyrene and benzanthracene exhibited similar distribution patterns in the studied area, implying that these compounds possess identical sources. Also, dibenzothiophene, a sulfur heterocyclic aromatic compound was determined in this study and it was not detected in all the samples analyzed.

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One of the major problems facing the existence of man in this millennium is pollution. Thus, it is no surprise that much attention is given to pollution control and remediation of polluted environment. While remediation can be achieved by physicochemical and biological methods, application of the latter tends to be gaining upper hand due to some of its inherent advantages. This study investigated the biodegradability of bitumen from Agbabu, Southwestern Nigeria by hydrocarbon utilizing strains of Pseudomonas putrefaciens, Pseudomonas nigrificans, Bacillus licheniformis, Pseudomonas tragi and Achromobacter aerogenes. The organisms were used to inoculate Mineral Salts Medium (MSM) supplemented with 0.2 g L-1 solution of Agbabu bitumen in dichloromethane. Cultures were inoculated at different temperature and pH (27°C/pH 3.5; 27°C/pH 5.6; 30°C/pH 7.0 and 40°C/pH 7.0) for two weeks. The quantity of bitumen degraded by each organism was determined gravimetrically at the end of first and second week. The rate of degradation was calculated for each organism and residual bitumen analyzed by infraredSpectroscopy. In the first week of incubation, Achromobacter aerogenes exhibited the highest rate of degradation (1.750±0.027 mg h-1 ) at 30°C and pH 7 while Bacillus licheniformis showed the least degradation rate (0.300±0.018 mg h-1 ) at 40°C and pH 7. Structural indices such as aromaticity, sulphonation, aliphaticity and oxidation calculated from the infrared spectra of recovered bitumen from the inoculated samples were different from that of the control. This thus, confirms the degradation capability of the bacteria used in this work on the Agbabu bitumen and hence their potentials for use in bioremediation of bitumen-polluted environments.

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Environmental challenges and decreasing fossil reserves due to increased utilization of fossil fuels have propagated the importance of alternative energy sources. Increased biodiesel production promoted excess waste crude glycerol leading to environmental issues, thereby inhibiting the sustainability of the process. This review paper discusses the different types of feedstocks utilized to produce glycerol-free biodiesel by reacting with methyl acetate via interesterification. Methyl acetate is used as an advantageous alternative to methanol in biodiesel production to overcome the environmental challenge associated with excess waste glycerol. The by-product, triacetin from the interesterification reaction, has shown excellent qualities as a fuel additive, thereby making the process cleaner and more sustainable as a result of not separating the triacetin from biodiesel. The resulting product referred to as biodiesel fuel (BDF) has been found to exhibit useful properties and applications as fatty acid methyl esters (FAME). The promising environmental and sustainability merits of the process far outweigh the slow interesterification kinetics demerits of the process, which can be overcome by suitable processing conditions. The prospects associated with biodiesel production by interesterification are also pointed out.

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